To extract liquid from the lower part of a case without splashing liquid to surroundings.

In this liquid extracting device, a mounting board 2 for being sealed and fixed to the case 1 has a drill passing hole 3, an outlet 15 side of an openable/closable gate valve 5 is communicated with the the drill passing hole 3 and is fixed to the mounting board 2. An inlet 14 and the outlet 15 of the gate valve and the drill passing hole 3 are arranged in a straight line, a drill 7 having an edge part 23 at the tip of a shaft part 22 is removably connected to the inlet of the closed gate valve via cylindrical socket 6. The inlet 14 side of the gate valve is closed by sealing between the socket 6 and the shaft part 22 of the drill, and the drill 7 inserted from the inside of the socket 6 into the inside of the opened gate valve 5 is disposed movably toward the drill passing hole 3.